To create a subdomain:
Log in to https://cp.controlpanel.systems
Head to Manage Hosting -> Manage.
Select the Subdomains icon.
You can then add your subdomain into the Subdomain field and select Create Subdomain. You're also able to change the Document Root so that you can direct the subdomain to the folder of your choosing.
What is the document root?
The document root is the folder which the subdirectory will use, for example, you may have a directory within your web space located within public_html called support (i.e. public_html/support), you could point your subdomain to this location by adding public_html/support in the Document Root field.
Note: Updating a document root can take ~15 minutes, so you may just need to be patient whilst that updates.